I have a exsting website https://www.journalsinsights.com/, now i want to install OJS in my website how i can?
OJS is a online publishing platform and you can install in on your hosting account main folder or in a sub-folder. e.g. https://yourdomain.com/ojs .
It all depends on how you would like to manage the install. Please, notice that it is not recommended to put OJS in the root folder of your domain along other CMS or online platforms. OJS has an index.php file that requires to be the main page of access for online access.
Best,
Israel