1) To use SofTek HubSpot theme first you have to create an account on CMS HubSpot.

How to create account CMS HubSpot - A tutorial on how to create your account CMS HubSpot.

2) After purchasing the theme from ThemeForest, download the zip file and then

Create and Publish a Page

In your HubSpot account, navigate to Marketing > Website > Website Pages.
In the upper right, click the Create dropdown menu and select Website page.
Hover over a template and click Preview in the upper right to see how it will appear on desktop or mobile device. To create a new page with this template, click the template.
After choosing template, choose Page.
Give your page an internal page name and click Create page.
Please note: you'll be required to give your page a public title in your settings before publishing it.

Setup Blog Listing and Blog Details Template

In you HubSpot account, click the Icon Settings in the main navigation bar.
In the left sidebar menu, navigate to Website > Blog.
In the top right, click Create new blog.
Set up your blog's name, language, URL and Meta Description.
Click Next.
Select a template for your Blog Post, then select a template for your Blog Listing Page.

In your HubSpot account, click the Icon settings in the main navigation bar
In the left sidebar menu, navigate to Website > Navigation.
Use the dropdown menu to select an existing menu to update. To create a new menu, click + Add menu.
Enter Menu name, after click Create Menu
Click Add menu item
Hover your mouse above or below an existing menu, then click the + icon and select an item to add to the navigation:
- Add item without link: adds another item to your menu that doesn't link to an existing page. This is often used as a placeholder for child menu items.
- Add page link: adds a menu item that links to a specific HubSpot page.
- Add URL link: adds a menu item that links to an external URL.
Give your menu item a name in the Menu item label.
Choose a HubSpot page or enter a URL for this menu item if you want it to be linked.
Choose Action
- You can also add a menu item by hovering over the right side of an existing item and clicking Actions > Add item below.
- Hover over the top-level menu item. Then click Actions and select Add child item below.
- If you want this menu item link to open in a new window, hover over the right side of the menu item. Click the Actions dropdown menu and select the Open link in new window checkbox.
To finalize the changes you've made to your menu, click Publish.

In your HubSpot account, click the Icon settings in the main navigation bar.
In the left sidebar menu, navigate to Website > Pages > Navigate to the Branding tab.
Upload your logo
Edit your logo's settings:
- In the Logo alt text field, add alt text that describes your logo's appearance and content
- To change your logo's dimensions, enter a width and height in the Logo width and Logo height fields.
- To direct visitors to a URL when they click on your logo, enter the URL in the Logo link field.
In the bottom left, click Save.

From editor home page move the mouse to the header and footer of the home page then left click mouse and choose Open in global content editor.
Edit the available modules in the header and footer.
After edit modules click Publish to return page editor.