Hi @sushumna, so happy that you are a fan of We Like Sharing! Even happier that you’d like to start your own photo bank! 
Take a look at what @cogdog and myself shared in Will “We Like Sharing” be back for 2024?
In a nutshell, you need to open a flickr account; this will work as your repository. The form works as a channel to receive submissions, so you decide what information you need from your participants. As an example, this is the form that I will use for the photo competition at TU Delft this year: https://bit.ly/OEPhoto24
When you start receiving photos, you need to upload them to your flickr account yourself, or get someone (a student, for example) to help you with that.
I’m not quite sure I understand your “Link to the Picture osted in flickr with #Welikesharing along with its description and License”… what do you mean?