After you install the forum, you will verify that the One Click theme comes with a default footer that you need to adjust to your needs.
To do that, you simply need to edit the file:

SERVER_ROOT/public_html/YOUR_FORUM_DIR/themes/oneClick/views/footer.php

You have some html classes that you can use it:

.responsive_img - to make images responsive
.row - to create a row with columns inside
.s1, .s1_2,.s1_3,.s2_3,.s1_4,.s1_5,.s2_5 - full, one half, one third, etc. columns for small displays
.m1, .m1_2,.m1_3,.m2_3,.m1_4,.m1_5,.m2_5 - full, one half, one third, etc. columns for medium displays
.l1, .l1_2,.l1_3,.l2_3,.l1_4,.l1_5,.l2_5 - full, one half, one third, etc. columns for large displays

If you want to add new classes it's recommended that you use the EXTRA CSS field from the Style Editor.

Optionally, if you want to add a banner or another element on the sidebar you can edit the file:

SERVER_ROOT/public_html/YOUR_FORUM_DIR/themes/oneClick/views/sidebar.php