Catchup TV or IPTV as it is also called such as BBC iPlayer, ITV Player, 4OD etc., arrives on your device via the internet. You don't 'cache' the internet. You must have a internet enabled device such as the Hummy or your smart TV. You also pretty much need an unlimited broadband connection of better than about 2Meg from your ISP as IPTV uses a LOT of data.
Your Hummy/TV then needs to be connected to your broadband connection, easiest is by Cat5 cable or those mains plug thingies.
Once connected, on the Hummy, for BBC iPlayer you tune it to BBC1 then press the red button. If you have the required internet connection to the Hummy, one of the options in the dropdown is iPlayer. Select it and wait for it to appear. If it's not there you don't have an internet connection. If you do have an internet connection, go to CH 903 to get ITV player. (it takes a few seconds to come up).
To check that the Hummy has an internet connection, select Menu ~ System ~ Network. You should have a number such as 192.168.1.24 in the IP Address, 255.255.255.0 in the Subset Mask, 192.168.1.1 in the Router Address, something like 192.72.240.0 in the DNS Address and a group of alphanumeric characters like xx-xx-xx-xx-xx-xx which is the MAC address of your Hummy on your network. Your addresses will probably be different to mine depending on your router., but are most likely to start with 192.168 etc. If you have nothing in the aforementioned fields, you do not have an internet connection to your Hummy and IPTV will not work.