You can select e.g. a horse as mount, or you understand it as "select amount"
Does that guide help?
To create a tx, the OP of the corresponding FLOT thread (in this case: https://discuss.nubits.com/t/flot-operations-sell-side-nbt-related/3118) has a lot of information, e.g. the redeem script including a link to Cointoolkit.
Creating a tx on Cointoolkit on mobile phone is...