Help plumbing drain lines for Separate Bath, shower and sink, single level house on crawl space

[cst1988]

Just as title states, I have a blank slate one floor house with a crawl space under. I am about to purchase parts to plumb drain lines and want to make sure I get the correct materials. There will be a separate garden tub, shower and sink only on this line, it also needs to include vents. Shower will have 2" P trap, bath will have 1 1/2" P trap. Could someone draw in or explain a simple design for me? Ideally this drain line will run thru the outlet hole between the tub and shower within the crawlspace. Thanks in advance