You want to create a post that will be the first that new members will see when they join your group.
This is easy to d with a “pinned” post. This is a great opportunity for you to welcome new members and add a link to your website to get more free traffic. Tell new members that they will find the latest and best information about your niche here.
Creating a video to add to your pinned post will help a lot too. Add a Facebook Group rules page to your website and add this link to your pinned post as well. Be sure to add any external URL’s before the “read more” cutoff occurs in the post.
You must add a call to action to your pinned post. This must be for new members to visit your website for a specific reason – you can provide an incentive for them to join your email list for example.
Other ways to get more Members for your Group
If you intend to run a high quality group with lots of valuable content then it will be pretty easy for you to get new members. The first thing to do is to add your new group to the menu on your website.
Many people will visit your website and never return, but they may well be interested in having your content show up in their Facebook news feed.
Another good way to get more group members is to partner with other groups in your niche. You should have already found some other groups in your niche where you are now a member so contact the owners to do a deal.
Ask them if they will recommend that their members should join your group if you do the same for them. Not all of the group owners will go for this but some will. Try to find related groups that are of a similar size for this method to work best. If you only have 10 members and you ask a group owner with thousands of members this is unlikely to work.
Use the “cross post” tactic with other related groups. First create a value packed post in your group that a lot of your members respond positively to. Then create a new post in other groups telling them that this is a cross post from your group. Some people will be curious about your group, check it out and then become members.