Opponents are the clubs and players you play against. Keeping the list clean is what makes match statistics add up: every game is attached to an opponent, so two spellings of the same club split that club's history in two.
Clubs and players
The screen has two tabs, and they hold different things.
Clubs — the teams you play. This is the list a game is attached to.
Players — individual opposition players, each optionally tied to one of those clubs. You need these only for sports where statistics are recorded per opposition player.
Add an opponent club
Go to Games > Opponents and stay on Clubs.
Click Create new.
Enter the Team name. It is the only required field.
Click Save.
Opponents are also created for you as a side effect of importing fixtures from a federation, which is the usual source of near-duplicates.
Add an opposition player
Switch to the Players tab and click Create new.
Enter a First name — required — and optionally a Last name.
Pick a Club to tie them to, or leave it as Select for an unattached player.
Click Save.
Merge two clubs
Merging is how you fix "IFK Göteborg" and "IFK Goteborg" sitting side by side. It moves one club's history onto the other and deletes the one it came from.
On the Clubs tab, tick exactly two clubs. Merge stays disabled until there are two.
Open the bulk actions and pick Merge.
Read the confirmation before agreeing. It names both clubs in the direction the merge will run — the first one you selected is merged into the second, and the first is the one that disappears.
Selection order decides which club survives. The confirmation spells out both names, so read it rather than trusting the order you think you clicked in. There is no undo.
Delete an opponent
Use the row menu for one club, or the bulk action for several. Deleting a club also deletes every opposition player attached to it — the confirmation says so, and it is easy to skip past.
Prefer merging to deleting whenever the club has been played. Deleting removes the record a past game points at; merging keeps the history and puts it under one name.
Find one
Search by name from the bar at the top. An empty result shows No result — No opponents found on the Clubs tab, No opponent players found on Players.
Troubleshooting
The same club appears twice. Almost always a fixture import against a slightly different name. Merge them rather than deleting one.
Merge is greyed out. It needs exactly two clubs selected — not one, not three.
No Opponents item in the menu. You do not have permission to see the opponent list. Ask a top-level administrator.
Statistics look split across two clubs. That is the duplicate above. After merging, the combined history sits under the surviving club — see View match statistics.