It is recommended that your chimney is swept every 6-12 months depending on usage. There is a high risk of chimney fires due to buildups in the liner if this isn’t done, it is also a good idea to have your stove serviced and checked over at least once per year, preferably before the winter so you can be sure it is safe to use before the cold weather comes and your stove is being used more frequently.
HETAS have provided a leaflet which has information about what fuel to burn and a handy safety checklist – you can see this here:
https://www.hetas.co.uk/wp-content/mediauploads/AFTERconsumer220118DIGITAL.pdf