Yesterday i got message from jack otarny i have send him

Yesterday i got message from jack otarny i have send him all information but did not answer the question i have people singing up but i always need to change the system because of plugins not working proper for example i activate debug addon for affiliates and send an affiliate link to jack but did not got response i will repeat my questions here and i hope i got some answers because i have one paid member first you tell me to use subdirectory for multisites and now i hear subdomains so i am trying to change everything to subdomains which means i have to change my video's also what i need to know now VERY URGENT if i change to subdomains what happens with the users which have already a subdirectory site can they keep there site or will they have problems to work on it if i need to transport all there information pages messages etc...to subdomains how i can do that?