How to solve the slow loading of website page after using theme

my Audioman pro theme How to solve the slow loading of website page after using theme. Using the default WordPress theme does not have the status of slow website loading. When using the AudioMan pro, there will be a problem of too high loading delay. I asked the server supplier that their technical support feedback is the slow website loading caused by using the third-party theme. How can I solve this problem. I am a user of paid purchase theme. I hope you can help me