show category in seprate page

Thank you for the kind words and for your questions. I have some experience with BuddyPress but I am not an expert in that plugin.

You wrote “I want to let my users upload any file and chose some tag“. MLA does not have specific features for uploading files and assigning tags and categories in the “front end” (users upload); the MLA functions for this task work in administrator mode. I think this is what you mean by your first problem, but if I did not understand perhaps you can say more about it.

Your second problem includes “how can I let my user chose a gallery in a single pages and I show all the gallery to him” There are two basic solutions I have worked with.

First, you can display a cloud of tags and let the user click on a tag so you can show a gallery of the items that have been assigned to that tag. One simple example of this solution is shown in the fourth post (my second response) in this earlier topic:

Att Categories menu returns 404 error

That topic has a lot of information about selecting items by tags and categories.

Second, you can let the user enter one or more keywords and then display a gallery of the items that have the keyword(s) in their title, description or tags. There are several examples of this basic idea in earlier topics such as:

Searchable media archive

If you go through those topics and the additional topics they link to you can find a lot of ideas on how to proceed.

Let me know if the information in those topics is helpful and give me any additional information you can on what you want to do within Buddypress. I will try to help you get the most of MLA for your application. Thank you for your interest in the plugin.