Board the train via the door marked with a bicycle symbol. When on board you will see the space allocated for bicycles. The Scotrail staff are usually pleased to advise if you are in doubt.

Scotrail like you to book a space for your bike when you buy your own ticket, although the bike booking is free of charge. Although on some Scotrail services cycle booking is not possible, and it is a case of first come first served. Even on the services where booking is compulsory, they will take you without a booking if no on else is booked on.
Does your gents racer know he may be in very close proximity to cycles of the opposite sex on the train journey? Better give him a wash, polish and lube. before you leave home.