I desperately need help with this pattern

I’m working on a cardigan and it tells me to do 5 rows in garter stitch which I did and then it says Change to stockinette stitch and increase 1 stitch each end of needle every 3rd row 0(0,0,6,0) times, then every 4th row 6(13,10,9,15) times then every 5th row 5(0,3,0,0) times. I’m working on the 2nd number in the parentheses so it’s 0, 10, 3. My question is what do I do with the first number which is 0 do I go down every 3rd row 6 times without increasing and then start with every 4th row increasing 10 times? Also I have another question. If a pattern gives you the largest size as a size large and you want to go up a size how much more do you cast on per size you want to go up? Please help me so I may continue this pattern. It seems like I’m always asking for help on here and everyone is such a big help. Thank you.

Ignore the 0s. So knit 5 rows, then switch to stockinette and increase every 4th rows 10 times. Period. You don’t do the every 5th row 3 times, because if you’re making the middle size, there’s a 0 on the 5th row instructions. Increase on the 4th row of stockinette (start it on the purl side so your incs are on the knit rows), then row 8, 12, 16, etc…
To go up a size larger than is printed, look at how many sts difference is given for sizes. Uually it’s 4, 6, or 8 or something between the sizes. To go up one size, CO that many more stitches for the fronts, back and sleeves.

so i totally ignore the every 3 rows and then just automatically start with every 4th row 10 times and then every 5th row 3 times. i don’t have to knit 18 rows to get to that every 4th row just do it immediately right?

Yep, start at the 4th row of the stockinette, then every 5th row after that. I misread the every 5th row instructions and thought that was for a different size.