How should I enter receipts for purchases made for tools, supplies and other expenses for my construction business? Would I enter Home Depot, Lowes, etc. under vendors?

You use Banking menu > Write Check, to enter payments by check or debit card. You use Banking menu > Enter Credit Card, for things purchased "on the card."

You can put those names as Vendor. For some, such as gas stations, I use "Other Names Lit" and a generic "Misc Fuel" or "Misc Supplies" since the gas station is Not a vendor name, they won't send you a bill to pay later and they are never subject to 1099-Misc reporting.

You can launch the program and at the No Company Open screen, bottom right is the big button for Sample Files. You want to open and use "product-based" = Rock Castle Construction, to Learn from.

Also open Help and leave it open while you work. Use it to Learn from. Search on "Work with Items" and "Job Cost Tracking." I will attach some images for your reference.

You use Items, not the Expenses tab, for the Job Tracking, since Job Reporting relies on Items.

Also, here are the video tutorials that used to be in the program, but Intuit removed them:

Desktop PC program video tutorials