How do I use a dildo for the first time?

I bought this 6” dildo from Amazon and I wanna try it out for the first time tmr. Tbh I never play with my hole. Fingering doesn’t feel good for me so there’s no point. I have plenty of astroglide lube.

For some reason the dildo doesn’t suction to wall so I think I’m gonna have to fuck myself girl style, or maybe ride it.

How do you warm it up only in the shower (warm water)? You lube up the dildo and your ass by rubbing and fingering the lube in?

How long do I need to take the dildo multiple times a week before I’m ready to bottom IRL or get an 8”?