Under the OPTIONS menu | EDITING tab, for Video Clip Transitioning choose ASK ME.
Then, when there is no excess video at the head or end of a clip, you should get a prompt. Tell it to Freeze.
Share a few clips where you want a transition, and how long they are to be, and someone will check them out...
Just upload the file/s to a free server, such as Google Drive or MS OneDrive, get a shared (public) link, copy the link and paste it here or to me in a Private Message via the mail envelope in the top-right corner of this forum.
Using Google Drive, if necessary change "restricted" to "anyone with link can view."