You have two options when uploading your amenities.
The first is to include them in the price, and make them free of charge, when a customer books a tour. The customer will see the amenity as „in price included“ when viewing the details of a package, or an amenity in a package.
The second one is to exclude them (set them as „additional“, when adding them to a product) and be able to price them later under „pricing“. If you choose to price them separately, the customers have the choice to book these additional amenities, or upgrades, when they look at the package.
Problem: You have a guide in English and Spanish included, but a Portuguese and a French speaking guide would cost extra.
Solution: Add the regular guide as an amenity and set them as „included“. Then add a second or third guide, with the description (e.g. „Book a French speaking guide“) and set them as „additional“. When you go to pricing, you will be able to add a price to the second and third guide. The customer will see the regular included guide and also the „Guide upgrades“ as a bookable option.