Adding the app
The Link Spotter app is available in the MS Teams app store. To add the app you can use the description under Add Link Spotter to a Team Channel or you can also have a look at the official Microsoft documentation about MS Teams apps: Apps and services
As an admin you have also the possiblity to go the admin center of your tenant to manage the apps. There you have some detailed options like making the app only available for certain teams or users.
Consent the app for your organisation
To make the app available for all your users, you have to add the app to a channel and open the app once. You may have to login first. Then the consent has to be approved for all users in your organisation. After the consent is approved, the other users can use and add the app to other channels without the need to approve the consent again.