Wordpress and Digital Ocean Problems

I can not edit my digital ocean files and can not update version of my wordpress. I need a skilled person to handle my issues. Therefore I am experiencing difficulties: 1. Plugins: as you know, one can't work on wordpress without installing admins. We have been trying to install plugins to wordpress, but every time we do, we get this message: "To perform the requested action, WordPress needs to access your web server. Please enter your FTP or SSH credentials to proceed. If you do not remember your credentials, you should contact your web host." We do have this FTP info but I can't seem to fill in the fields, like hostname and FTP password; you can see in the attached screenshot. 2. Landing page URL: we created a landing page template for our upcoming Facebook campaign. We are looking to create a custom link for the landing page with our domain name. We used unbounce to create the landing page template. How can we create a custom domain for our landing page? 3. Broken Links: we have several broken links in our English and Dutch websites. Below are the broken links: [login to view URL] [login to view URL] 4-Images: We are having some difficulty uploading some images. You can see the images in the attached files. These images should be uploaded in the hair transplant section on this link: [login to view URL] 5. Widgets: We are not able to install widgets for the website. 6. Language button: Language selection on the Dutch website should have the English language button. And vice versa. 7- Slider Text: How can we edit the text in the slider carousel on the homepage? Will you be able to help us with that?