Congratulations, Brammofan. Frankly, you were lucky to find an O-ring chain that used a spring clip to secure the master link pins. Most O-ring chains on the market use a rivet-type master link that requires you to use a somewhat expensive tool to flare the ends of the link pins to keep the end plate on.
Anyone purchasing an O-ring chain should verify that it comes with a master link that uses a spring clip - or plan on purchasing one of several chain riveting tools that are on the market, such as sold by Motion Pro, Cycle Gear, RK chain, etc. Expect to pay anywhere from $80 to $180 for the tool. The more they cost the better the quality. I own and have used the Motion Pro tool for years and it works well. I believe that Motion Pro has just introduced a new simple and compact combination tool that will break the chain, press on the link plate and also rivet the pins. It looks like a good tool to me and seems to be easier to use than their old chain-breaking tool kit like I have.