Well, this is a can of worms. Okay, so I will assume you've already GOT a "home studio setup" since you're referring to one in the possessive. Good start.
If there are drums, that's what you start with, whether they're real or (more likely in a home studio) software-based. Work out your drum parts, choose your tempo (BPM) and get them drummies into the DAW (Digital Audio Workstation) first.
After that, in a typical studio, the bass guitar might be next, but when we guitarists record, we tend to not have bass parts all written out yet, so record your rhythm guitars. Assuming we're talking about a rock song, typical approach is two separate rhythm guitar tracks, and you pan them left and right, usually really hard left and right or even 100 left and 100 right.
Then you can do either the bass or the melodic parts/instruments - guitar melodies, keys, vocals, etc.
Let's start there, because for 4 songs, that's probably anywhere from a week to several months' work, depending on your priorities, how good you are in a studio setting, and how picky you are.