How to fix these errors..

I would like to add this plugin https://www.ads-software.com/extend/plugins/booking/

To this website. . https://phatlenzphotography.com/index

But I need to fix these errors for the pages lot load correctly.. How do you fix this?

Error: $ is not a function
Source: https://phatlenzphotography.com/index/wp-content/themes/dt-crea/js/slider.js
Line: 6
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Error: $ is not a function
Source: https://phatlenzphotography.com/index/wp-content/themes/dt-crea/js/plugins/placeholder/jquery.placeholder.js
Line: 60
———-
Error: $ is undefined
Source: https://phatlenzphotography.com/index/wp-content/themes/dt-crea/js/plugins/validator/z.trans.en.js
Line: 1
———-
Error: $ is not a function
Source: https://phatlenzphotography.com/index/wp-content/themes/dt-crea/js/sc-slider.js
Line: 1
———-
Error: $ is not a function
Source: https://phatlenzphotography.com/index/wp-content/themes/dt-crea/js/vt.js
Line: 10
———-
Error: dt_settings is undefined
Source: https://phatlenzphotography.com/index/#go_page_58
Line: 102
———-
Error: dt_settings is undefined
Source: https://phatlenzphotography.com/index/wp-content/themes/dt-crea/js/vt.js
Line: 1225