Can't Approve document

[umidjons]

First, thanks to developers for this kind of great app.
I've installed letodms successfully.
Then I add 2 groups to the system, each group have 2 users.

group1
user1 - manager
user2 - user
group2
user3 - manager
user4 - user

user3 create new document and adjust permissions for user1 (read and write access). user3 also assigned user1 to reviewers and approvers list. user1 can write Review, but couldn't see any link to approve document. Please, help me, how to give access for approving documents?
Thanks you in advance!