adding object(s) to a photo

[scooby doo]

hi guys

girl i met few days ago wants me to photoshop her dog with scuba tank and other equipment (mask..)
thats too much for my skill level that is almost equal to zero

can someone please photoshop scuba tank on the dogs back and make it like hes breathing from it?

i must capture her heart, please help!

thanks for help and sorry for being a leech!

 

[HuckinFell]

Something like this?

 

[scooby doo]

man, this is brutal!

good job, cant thank you enough!

<3