I'm going to replace my host os on my shitty laptop with Linux specifically puppy Linux or alpine Linux from scratch and I need to know how will I get started and make it easier for myself, I use a HP notebook 540
You might want to think twice before using unique, niche distros like GoboLinux, Alpine, or NixOS. PuppyLinux doesn't look like a proper distro, more like the equivalent of EndeavourOS or Artix. Since you're using Linux for the first time, why not use Linux Mint, Ubuntu or Fedora?
Like the others, I suggest you stick to a distro designed for desktop use (Ubuntu, Fedora etc), you'll have a much easier time.
If you really want to go with something closer to "scratch made" I'd recommend Arch. Its documentation is killer and you can build a system suited to your requirements.
May I ask why you, as a beginner, specifically chose one of those distros instead of more "mainstream" ones?
Puppy Linux's main use-case is to be a live ISO, that doesn't need to be installed to run. It doesn't mean it's not a good idea to install it, but I think if you want to use an Ubuntu derivative, there are better options for a beginner like Pop or Mint that would let you install a lightweight desktop environment like XFCE, LXDE, LXQt and so on.
Alpine Linux is specifically designed to avoid all the core system tools that are pretty much universal on most other distros like glibc, systemd or GNU tools and libraries, which will make your life hell as a beginner if you need to troubleshoot anything as most "universal" documentation like the Arch wiki would be at best partially relevant, at worst useless.
For starters, consider another distro if you want to make things easy on yourself. Alpine is probably a poor choice unless you have a reason to use it. I guess you could use it as a desktop if you really want to, but it’s more geared for containers and embedded devices. It uses musl instead of glibc so you will have problems running software that isn’t packaged for Alpine. The issue with Puppy is you will have a hard time getting help when you need it because it’s kind of a niche distro.
For your first time, you’re better off using something more mainstream. You are going to run into some issues and it’s a lot easier finding solutions for popular distros. Debian would be a fine choice because it’s widely used and runs great on older hardware. Beyond that, you could look at Ubuntu, Fedora, PopOS and Mint.
It seems your machine has 4GB of RAM, in which case you can run KDE (for example) quite comfortably and don't necessarily need a lightweight-focused desktop environment. So I'd say to go with a popular distro, as the other comment suggested, and not a niche one. Then pick the DE you like from videos/screenshots.
You can install any general purpose distro (debian, opensuse or one of that others suggested) with a lighwwight DE (LXQT, Xfce, MATE) and it will work well. However when you run a browser and open several tabs with heavy websites it will become very slow. It does not matter what distro you use. You need 8G+ of RAM for comfortable web serfing nowadays.
My Linux knowledge isn't what it used to be, but I believe you can easily make a thumb drive with a bootable distro. I would recommend taking whatever you choose for a test drive before you wipe a working system. That way you can see if there's any weird stuff that doesn't want to work.
Since it’s your first time, my first suggestion is to try Xubuntu (Ubuntu with XFCE desktop) or Kubuntu (Ubuntu with KDE desktop and generally more popular than Xubuntu). Both distributions are lighter on resources and they have an Ubuntu base which means there’s a ton of documentation online so if you run into problems, you will have plenty of resources.
Alpine is small for sure but it is more niche and it doesn’t use systemd which most major distributions use which means if you happen to run into weird issues, your pool of resources will be smaller. Don’t get me wrong, Alpine is great but I wouldn’t recommend it for new users. I don’t know anything about Puppy Linux; maybe it’s fine?
If your machine can’t run Xubuntu or Kubuntu, then worry about trying more niche distros like Alpine or Puppy.
If you run into issues, feel free to ask questions. The community is generally nice but you’ll want to try fixing it yourself first and then including what you tried in your post to get a better reception.
Embrace the terminal. It’s daunting at first but it’s such a powerful tool. Don’t use sudo with every command. Don’t paste random command in the terminal without doing a little research to understand what they do. Again, ask if you need help, you won’t learn everything overnight.
Good luck!
Edit: Linux Mint is also probably a good choice. Never used it myself but I’ve heard good things.
I struggled with Kubuntu as newbie (coming from Windows) - Mint was easier for me and I sticked with it (Cinnamon in my case, but my laptop is more powerful)
I appreciate what KDE is doing with their DE, I’m glad it exists but it’s not for me either. I only suggest it because it’s surprisingly light on resources for the amount of customization options you get.