How to design this table?

How to design this table? If there is a user reply content under the content published by a user, will each topic and its reply be in the same table?

Reply to discussion (solution)

Topic
Reply to a table

The basic table structure is as follows:
Topic
Id, user_id, title, content, addtime, lastmodify

Comment
Id, topic_id, user_id, content, addtime, lastmodify

Topic
Reply to a table

The basic table structure is as follows:
Topic
Id, user_id, title, content, addtime, lastmodify

Comment
Id, topic_id, user_id, content, addtime, lastmodify

How can we establish a connection between the two tables?

The topic table id corresponding to the topic_id of the comment