I’ve noticed most of the companies I shop for pay around mid month the month following when the shops are completed. For example, all the shops that I complete by the end of January will typically pay between the 15th and 20th of February.
As for advice, I suggest setting up the spreadsheet and keeping track of all your shops, their information, what the pay, bonus, or reimbursement is, etc. With how many companies I shop, this makes it easy for me to find all my information in one place and to keep track of which ones have paid and which ones haven’t. You’ll also want a separate one for your mileage which you’ll need this when you file taxes. Also set up some sort of spreadsheet or note for all your logins.