Sorry, I'm wanting to do a mech with him finding parts with them having stats, but no levels or anything like that
Ahh... okay. That makes sense. Thank you.
Since you mentioned writing in Google-Docs and wanting to insert tables, you'd approach that by selecting Insert--> Table--> 2x? [or ?x2]
You'll want a two-column table ideally, but the number of rows would change based on the number of 'stats' you want each part to have.
You'll also probably want the mech itself to have a set of 'Base Stats' that the interchangeable parts can modify. (+% would be ideal in some cases)
IE: The mech has a base 'mobility' stat (for its core structural capabilities).
Swapping Thrusters (an interchangeable part) could boost the 'base stat' by 50% but wouldn't impact it's armor stat at all.
While swapping let's say, and Arm, will modify the core structure, and thus, alter the 'Base Stats' of the mech.
The same kind of thing, for swapping a 'head' or 'sensor array'. It will impact detection ranges and accuracy, but not mobility.
Ultimately it depends on how nitty-gritty you want the engineering and stat aspects to function. Best advice I can offer, is to be consistent. Design your system, then fit the parts into it. That way, as your readers understand the underlying system, the rest will all make sense, and it will be easier to figure out how different parts can potentially impact the mech(s) overall.
No levels anywhere if you don't want them; but I would suggest (in lieu of levels) that assigning the mechs at least a base 'tier' or 'ranking' will also help quantify things for LitRPG lovers.
Same for Parts and if you really want to get down to it, pilots (based on skill) could also have ranks. [A, B, C, D, etc etc]
Zoids: New Century Zero did something like this (albeit they did not do so well with making it matter, it was more just arbitrary to say 'this pilot is good, but this one is better' type things)
IE:
Pilot A has a ranking of '
B-rank' and
Pilot B has a ranking of '
D-rank'. If they were to face each other in a duel, using equal mechs, Pilot A would probably win, because they have the higher skill-rank. You can swap pilots for mechs too. If a Mech is 'A-rank' it could be significantly more powerful than a 'C-rank' mech, and assuming equal pilot skill, the A-rank mech will likely come out on top in a duel.
If you're planning to include anything along those lines (would recommend it), you'll also want to consider how the rankings are determined, and why they matter. Otherwise, you can leave that stuff in external author's notes (and glossary entries here on SH) for die-hard fans without really getting too deep into it in the narrative itself.
If you're wondering about how many different stats to include; probably somewhere between six and ten would be ideal. It's enough to have variety, but not so much that it drags down the narrative.
Hope this helps.