Specify your timelock admin in timelock-config.js.
Edit kovan.js or mainnet.js with data you want before sending queue transactions.
truffle exec scripts/timelock/timelock-batch.js --network kovan --type queue
Specify the network type as you need.
A new json file named with timestamp would be created in data after sending queue transactions, like 2020-10-30T13:18:33.795Z.json
NOTE: Keep this file until you send execute txs.
Make sure the json file from queue exists in data. With file 2020-10-30T13:18:33.795Z.json,
truffle exec scripts/timelock/timelock-batch.js --network kovan --type execute --data 2020-10-30T13:01:17.023Z.json
Specify the network type as you need, while it should be the same as the type you use for queue.