how to make a relationship between 3 tables using the Join() method and using two values ​as a rule Entity Framework

Question

I trying to join 3 tables and I need to compare two values to make the first relationship, and make the second relationship based on that. But I don't know how to use the Join() method to do that.

I need to return value when PRTCL_BLQ and SQ_BLQ of TB_TABLE_1 is equals PRTCL_BLQ_VL and SQ_BLQ_VLR of TB_TABLE_2.

After that I need to compare the VARAJUIZO_BLQ_VLR of returns with VARAJUIZO of TB_TABLE_3 and than return the NM_VARAJUIZO and TRIBUNAL values.

I have these 3 tables:

First table:

namespace Infrastructure.Data.Model
{
 using System;
 using System.Collections.Generic;

 public partial class TB_TABLE_1
 {
    public decimal Attr1 { get; set; }
    public decimal Attr2 { get; set; }
    public string Attr3 { get; set; }
    public Nullable<decimal> Attr4 { get; set; }
    public string PRTCL_BLQ { get; set; }
    public string SQ_BLQ { get; set; }
  }
}

Second table:

namespace Infrastructure.Data.Model
{
 using System;
 using System.Collections.Generic;

 public partial class TB_TABLE_2
 {
    public decimal Attr1 { get; set; }
    public decimal Attr2 { get; set; }
    public string Attr3 { get; set; }
    public Nullable<decimal> Attr4 { get; set; }
    public string PRTCL_BLQ_VLR { get; set; }
    public string SQ_BLQ_VLR { get; set; }
    public string VARAJUIZO_BLQ_VLR { get; set; }
  }
}

Third table:

namespace Infrastructure.Data.Model
{
 using System;
 using System.Collections.Generic;

 public partial class TB_TABLE_3
 {
    public string VARAJUIZO { get; set; }
    public string NM_VARAJUIZO { get; set; }
    public string TRIBUNAL { get; set; }
  }
}

Query

return db.TB_TABLE_1
          .Join(TB_TABLE_2,
                tb1_prtcl => tb1_prtcl.PRTCL_BLQ,
                tb2_prtcl => tb2_prtcl.PRTCL_BLQ_VLR
                {}) //I don't know how to compare the 2 values (PRTCL_BLQ and SQ_BLQ) and continue that to join the third_table =(
          .Where(x => x.Attr1 == attr1 &&
                      x.Attr2 == attr2 &&
                      x.Attr3 == attr3)
          .ToList()
          .Select(x => new ReturnClass
           {
             Value1 = x.Attr1
             Value2 = x.Attr2
             Value3 = x.Attr3
             Prtcl = x.PRTCL_BLQ
             Sq = x.SQ_BLQ
           }).ToList();
}