For tours in Gibraltar, there are a few options.
For The Top of The Rock under your own steam, it is quite a long walk up! or you can get the public bus to Willis which will cut out most of the walking but not all as it is all spread out across the top of the rock.
The cable car is the most popular and the view going up is spectacular on a clear day! Or there are taxi tours.
If you do not fancy the top of the rock there is plenty more to do, like Dolphin Trips at Ocean Village Marina, The Spirit of The Rock Gin Experience for the adults in your party, Historic walking tours and The Gibraltar Museum, sit and relax at either of the marinas or check out the beaches or check out the views across to Africa and Spain from Europa point. (Get a bust to Europa Point it is a long walk)
I have done most of it and the most interesting were the World War Two tunnels and The Gibraltar Gin Experience!
Have a great trip to Gibraltar.