JWs believe that the apostles and faithful dead went to heaven in 1918 i.e., the first resurrection began in 1918. That resurrection will be complete within the lifespan of a single overlapping generation.
While that is true they also teach that the resurrection has not even begun yet and will begin with Jesus' Matt 24:30 arrival when the 1,000 years begin...
[John 6:39 This is the will of him who sent me, that I should lose none out of all those whom he has given me, but that I should resurrect them on the last day.]
[7-1-98 WT p.21 par.12 - That “last day” coincides with the Thousand Year Reign of Christ. (Revelation 20:6) Imagine the excitement during that “day” when this grand event begins!]
[5-1-90 WT p.26 par.9 - Martha knew about that hope from her association with Jesus, for she had previously said to him regarding Lazarus: “I know he will rise in the resurrection on the last day.” (John 11:24) She knew that the resurrection would be, not on his (Lazarus’) last day, but in the future, “on the last day”—Judgment Day, when the dead would be raised under God’s Kingdom rule.]
[12-1-89 WT p.9 - The judgment will take place “in the last day,” during Christ’s Thousand Year
Reign.]