I don't have the wallet in front of me at the moment, but something like this:

1) Enable Coin Control
- go to 'Settings' -> 'Options' -> 'Display'
- check 'Display coin control'
- confirm with 'OK'

2) Select the inputs you want to split
- open 'Send', open 'Inputs'
- here you can see all inputs (transactions sent to your wallet), there should be at least one (the amount you received some days ago)
- select the inputs you want to split (e.g. all inputs with a balance > the mentioned 1000 to 2000 QBT)
- copy one of the input addresses (we will send the selected coins later to this address)
- confirm with 'OK'

3) Split the inputs
- back in the 'Send' dialog, check 'SplitBlock'
- you can now enter the number of 'blocks' you want to generate (the term 'blocks' might be confusing, it's the number of outputs/new inputs you want to create) - let's say your input(s) contain(s) 10000 QBT and you want to split them to new inputs with the mentioned 1000 QBT, you should enter 10, because 10000 / 1000 = 10

4) Send your QBT
- paste the address from 2) into the 'Pay To:' field
- copy/paste or enter the amount from 'After Fee' (this should display the amount of your input(s) - the transaction fee) into the 'Amount:' field
- confirm with 'Send'

This will create a transaction, splitting your coins. You can check the 'Transactions' tab, it should be listed. Wait some minutes. You can verify via 'Send' -> 'Inputs' if there are more inputs than before (in our example from above, you will now see 10 inputs with 1000 QBT each).

Hope this helps!