Explain the freelancer well and provide them with sufficient material so that they can work peacefully. Also, if you are looking for ad services, you must mention the platform on which you are looking to advertise your products. Ask your freelancer to Create a sales page [สร้างเพจขายขอ,ง which is the term in Thai] for better advertisement.
Also, you have to clear about the target audience
You must be very clear about the reach and the target audience that you are rooting for. If you are not telling the right kind of information, then you are definitely going to fail on the amazing platform. However, if you hire the right person and get the job done through him/her, then obviously your business will get a boost, and your products will generate a lot of clicks and views if you Get ads for Google ads [รับทำโฆษณา Google Ads which is the term in Thai]
The clicks and views themselves are not sufficient until they are converted into actual buyers
Now the main task is to convert the clicks and views into actual buyers. Nonetheless, just leave everything to the freelancer and ask them to help you out in such scenarios. The freelancers working at fastwork or other freelancing sites have great knowledge of the field they are working in.
So, you can definitely discuss your queries with them. You should never hide anything from your freelancer just because your freelancer needs to have total information about which targets to achieve.
So, if you are not discussing your requirements with your freelancer, then there will be high chances that you are going to get your work ruined. Always trust your selected freelancer and ensure that they have got each and every file of the requirement.