Error implementing Paging in MVC C#

First, You need to Install this package using Nuget manager console(In VIsual Studio,Click on Tools-> NuGet Package Manager -> Package Manager Console) using this line

Install-Package PagedList.Mvc 

After installing it reference it in your controller, your error of ToPagedList should get resolved.

For Second error,

The model item passed into the dictionary is of type 'System.Collections.Generic.List`1[MvcApplication3.TeleInfo]', but this dictionary requires a model item of type 'PagedList.IPagedList`1[MvcApplication3.TeleInfo]'.

You need to change the @model type at the top of your view.

It should be changed from

@model IEnumerable<MvcApplication3.TeleInfo>

to

@model PagedList.IPagedList<MvcApplication3.TeleInfo]>
@using PagedList.Mvc; 

Read the article carefully, it is given there, it will resolve your error for sure, thanks

the error is may be because your Model is not returning .OrderBy Data

I.e.  instead of 

return View(ModelList.ToPagedList(pageNum, pageSize));

You should change your code to:

return View(ModelList.OrderBy(x => x.Any_Column_Name_To_Order).ToPagedList(pageNumber, pageSize));

try the above changes, plus the changes mentioned in above answer, it should resolve both of your issue's, let me know by commenting if it works, thanks