Minecraft – Do /tellraw selectors refer to the reader or the executing entity/block

You can use scoreboard in player selectors to find out which one they clicked. Usually this is done by either testfor or execute.

I recommend a 20 t/s clock to check these as soon as they click it. You don't have to use one, but it may help. great method to setup one.

In the case of testfor, it is actually not recommended to use it. You can't exactly distinguish which player clicked it, you just know that it was clicked. A better way is the execute method. Never-the-less, the command should look like this:

Testfor @a[score_test=1,score_test_min=1]

You will need a comparator to get if it succeeded to find it. You should also have a separate command block for each, then change the 1 to another number for each possible outcome.

In the case of execute: recommended method. You can use @p in the command part to target that specific player. Command as follows:

Execute @a[score_test=1,score_test_min=1] ~ ~ ~ <command>

For this, you should set their score of that to 0 as soon as the command is run, otherwise that command may be run twice.

Adding a converter

Since you have one objective that has all the time in seconds, all you want to do is essentially subtract 60 seconds off of the objective and add a minute to a separate score for every 60 seconds. You can do this by adding a clock that does a /testfor to test if the player has at least a score of 60 for the objective best. You can get the output from that command using a comparator and, when that result is true, have two other command blocks that will subtract 60 seconds and add a minute to the player's score. The remaining seconds will be converted to bestsecond and the minutes will be bestminute. That's it!