Let dogs see you do it first, don’t force them on, their curiosity and desire to be besides you will get the better of them. Some will swim towards your board, help them on placing your hands under their paws for traction, be in a kneeling or seated position to avoid tipping. As they climb on from side larger dogs can tilt or tip your board. They make doggy deck pads for them to sit on but when they get that itch to jump off you have to let them go. A leash can be used to train them to stay but it shouldn’t be attached to you or board, you could try standing on the strap but this is really only to train them to sit and stay on the board, not for paddling anywhere. Be sure you are comfortable enough to not fall on them or hit them w paddle when falling. A seasoned SUP PUP can be your best paddle buddy, Just be patient and try to avoid new distractions they might not be familiar with.